Android girls are nothing new especially with emotions but Isla doesn't do anything for me.

Giftias are androids with human emotions with a strict lifespan of 81,920 hours, which roughly translates to about 9 years and 4 months, after which they lose their memories, breakdown in personality and go rogue leading to a potentially life threatening scenario. (Spoilers it rarely happens)
The lead characters work for the Terminal Services that retrieve Giftias nearing the end of their lifespan. Isla is a Giftia who eventually falls in love with lead character Tsukasa but is nearing the end of her own lifespan and inevitably this is how it ends, hardly a spoiler as it's the only logical end to a story like this as in keeping with the Anime's Universal Law.
Where I lose attachment to the character of Isla is for four reasons.
1. For the most part particularly early on, Isla still acts like an android, other androids with emotions like in Mahoromatic and Saber Marionette act human.
2. Even when she does start acting more human over the course of the story, her voice and cute actions fail to win me over, there's way too many comparisons between her and characters like Rei Ayanami and Ruri Hoshino.
3. The ending depending on your interpretation essentially retcons the whole anime, making her deactivation kind of meaningless.
4. You'd think a company like SAI Corp would improve the lifespan of their androids over the span of a minimum of at least a decade.
I mentioned Mahoromatic earlier that shares the same plot, Mahoro also has a limited lifespan which is more emotional for two reasons.
1. You always see a countdown no matter if the episode is comedic or serious.
2. The tragedy is way more impactful when it does happen and completely changes Suguru's destiny, something that Tsukasa never suffers from, he got his job by good connections rather than being qualified for the job and while it is sad to see Isla go, his whole job is essentially recreating the same painful scenario of losing a loved one with every Giftia they retrieve, Tsukasa will not be any different when he returns to work apart from being a little bit wiser.
A better ending for Plastic Memories would be seeing Isla go rogue and Tsukasa having to destroy her, this isn't me being cruel, I just want a better ending.